It is universal but it is a very easy box to fit in. You won' need the hole in the firewall for your blower motor anymore as it is contained in the box. All you need is a spot for your heater and A/C hoses to enter once you figure out where you want the box. I ran mine up in the wheel well to keep my firewall cleaner looking.
I guess you could get (or make) one of the round aluminum plates to cover the hole in your firewall and run your hoses through that since your car is already done and so damn nice!!